A pretty nonsense functionality.. this way of course but may help..

Code:
Sub OverloadStr( ByVal sParam As String )
    MsgBox "String: " & sParam
End Sub 

Sub OverloadLng( ByVal lParam As Long )
    MsgBox "Long: " & Format$( lParam )
End Sub 

Macro MySimpleOverload( p1 )

    MacroTemp v
    Dim v As Variant
    v = p1
    If VariantVT( v ) = %VT_BStr Then
        OverloadStr( Variant$( v ) )
    Else
        OverloadLng( Variant#( v ) )
    End If

End Macro
Usage:
Code:
    MySimpleOverload( "hello" )
    MySimpleOverload( 1234 )